Yu. V. Kurbatov

Reductive Amination of Quinoline N-Oxide with Aminopyridines and Their N-Tozyl Derivatives

In reaction of quinoline N-oxide with 2-aminopyridine in the presence of tosyl chloride the substrate undergoes reductive amination into 2-pyridyl(2-quinolyl)amine, and with 3- and 4-aminopyridines reductive tosylamination occurs to furnish N-tosyl derivatives of the corresponding 3- and 4-pyridyl(2-quinolyl)amines. N-tosyl derivatives of aminopyridines also react along reductive tosylamination pathway.

Reductive acylamination of pyridine N-oxide with ethylenediamine and phenylenediamines

Reactions of pyridine N-oxide with ethylenediamine and o- and p-phenylenediamines in the presence of p-toluenesulfonyl chloride in alkaline medium lead to the formation of the corresponding N,N′-bis-(p-tolylsulfonyl)-N,N′-bis(pyridin-2-yl)diamines as a result of reductive acylamination.

Flavonoids fromAmmothamnus lehmannii

We have previously isolated phenolic acids from the plant A~ot~nu8 ~e~z~anni Bge [1]. Continuing our investigation, from an ethyl acetate fraction of an alcoholic extract of the epigeal part of the plant collected in the flowering period in the Kenimekh region of Navoi province (close to the village of Kokcha), we have isolated another five flavonoids by column chromatography on silica gel with elutlon by chloroform-ethanol in various ratios.

Structure of a new chalcone ammothamnidin fromAmmothamnus lehmanni

A new chalcone ammothamnidin with the composition C25H28O4, mp 112–114°C [α]D20 + 4.5° (methanol) has been isolated from the epigeal part and roots ofAmmothamnus lehmanni Bge. On the basis of chemical transformations and IR, UV,1H and13C NMR, and mass spectra it has been shown that ammothamnidin has the structure of 2,2′,4′-trihydroxy-3′-(2″-isopropenyl-5″-methylhex-4″-enyl)chalcone.

Reductive acylamination of pyridine N-oxide with aminopyridines and their N-p-tolylsulfonyl derivatives

Pyridine N-oxide reacts with 2- and 3-aminopyridines and their N-p-tolylsulfonyl derivatives in alkaline medium in the presence of p-toluenesulfonyl chloride to give N-p-tolylsulfonyl-2,2′- and 2,3′-dipyridylamines, respectively, as a result of reductive acylamination. In the reactions with 4-aminopyridine and 4-p-tolylsulfonyl-aminopyridine, their N-p-tolylsulfonyl- and N,N-bis(p-tolylsulfonyl) derivatives are formed, while reductive acylamination does not occur.

Chemistry of heterocyclic N-oxides and related compounds 13. Acylamination of pyridine N-oxide by aniline, p-anisidine, and their N-p-tosyl derivatives

Acylamination of pyridine N-oxide by aniline, p-anisidine, and their tosyl derivatives was carried out in an alkaline medium in the presence of p-tosyl chloride. The reaction proceeds selectively with the formation of the corresponding 2-(N-p-tosyl) anilino- and 2-p-(N-p-tosyl)anisidino-pyridines. The reaction products were converted by acid hydrolysis into the corresponding 2-anilinopyridines.

Chemistry of heterocycylic N-oxides and related compounds. 12. Diphenylhydroxymethylation of quinoline N-oxide with benzophenone ketyls and dianions

Diphenylhydroxymethylation of the pyridine ring to give diphenyl(2-quinolyl)carfabinol or its N-oxide occurs in the reaction of quinoline N-oxide with benzophenone ketyls and dianions. The best results are obtained when the lithium ketyl is used. A reduction product, viz., quinoline, is formed simultaneously in all of the reactions.

Chemistry of heterocyclic N-oxides and related compounds. 11. Reaction of pyridine N-oxide with metal ketyls and benzophenone dianions

The reaction of pyridine N-oxide with metal ketyls of benzophenone was studied. It is shown that diphenyl(2-pyridyl)carbinol N-oxide is formed with the lithium and sodium derivatives of benzophenone, whereas diphenyl(2-pyridyl)carbinol is formed with the potassium derivative of benzophenone. Diphenyl(2-pyridyl)carbinol N-oxide is obtained in lower yields in the reaction of pyridine N-oxide with benzophenone dianions. Pyridine and 4,4′- and 2,2′-dipyridyls are simultaneously formed in all of the reactions.

Reactions of aniline with alkali metal diphenylketyls and dianions derived from benzophenone and Michler’s ketone

Potassium diphenylketyl and benzophenone dianion react with aniline to afford N-(diphenylmethylene) aniline. Under analogous conditions, the corresponding sodium and lithium derivatives undergo disproportionation with formation of triphenylmethanol, benzoic acid, and diphenylmethanol. The condensation of potassium and sodium bis(4-dimethylaminophenyl)ketyls and salts with Michler’s ketone dianion leads to formation of N-[bis(4-dimethylaminophenyl)methylene]aniline, while lithium bis(4-dimethylaminophenyl)-ketyl and Michler’s ketone dilithium salt are reduced to bis(4-dimethylaminophenyl)methanol.

Organic acids ofAmmothamnus lehmannii

To isolate the phenolic acids, concentrated ethanolic extracts of various organs were diluted with distilled water (i:i) and extracted exhaustively with ether. The ethereal extracts were washed with 5% sodium carbonate solution and then the aqueous solution was acidified with 5% sulfuric acid and re-extracted with ether. The combined phenolic acids so obtained were separated by column chromatography on silica gel and cellulose in a gradient hexane--acetone system. In this way, four substances of phenolic nature were obtained which gave positive reaction with a number of reagents for phenolcarboxylic acids [2]. These acids were identified on the basis of their UV and IR spectra, and also by direct comparison with authentic samples.